1. Technical Field
The present invention relates to a method for manufacturing a semiconductor device, the semiconductor device, a semiconductor circuit, an electro-optical device, and an electronic apparatus.
2. Related Art
In recent years, researches on an organic device become more and more active because it is anticipated to be light weight, flexible, and at a low cost. In particular, an organic thin film transistor (hereinafter, abbreviated as “TFT”) is increasingly expected to be applied to electric papers, wireless tags, plastic IC cards, and further, in fields of medical application such as biosensors for practical use.
As a process for manufacturing an organic TFT, vacuum processing such as vapor deposition, and a coating process such as spin coating and an inkjet method are applicable.
Since such coating process is simply and easily conducted in the atmosphere, it is said that it has more advantages than the vacuum processing in broadening areas and cost reduction.
A gate insulation layer formed by the coating process as the above is required to have conditions such as high characteristics as a TFT (an ON/OFF ratio, an S value, and an ON current value), low hygroscopicity, heat resistance, high-molecular weight, solvent selectivity, and a favorable film forming property. (e.g. JP-A-2006-297694)
For example, if polystyrene is used as a material forming a gate insulation layer, dielectric breakdown immediately occurs to the gate insulation layer in the atmosphere.
If polymethyl methacrylate (hereinafter, abbreviated as “PMMA”) is used as the material forming a gate insulation layer, high hygroscopicity of PMMA causes deterioration of the TFT characteristics in the atmosphere.
Further, if a polymer that has high heat resistance is used as the material forming a gate insulation layer, the gate insulation layer becomes hard to dissolve in a solvent because the polymer has rigidity. As a result, the gate insulation layer cannot be formed.
Therefore, a material that is applicable and can satisfy the conditions of the gate insulation layer described above has not yet been found.
On the other hand, to improve TFT characteristics, a method to make a gate insulation layer thinner has been known.
However, the gate insulation layer made thin has a high incidence of dielectric breakdown, thereby having an issue in which devices lack reliability. Therefore, an organic TFT made of an insulating material that is hard to cause dielectric breakdown (with a high withstand voltage) even if being made thin is required.